Mesothelin (EP140)

Mesothelin is a 40 kDa glycosyl-phosphatudylinositol-anchored glycoprotein cleaved from a 71kDa precursor protein encoded by the human mesothelin gene. Mesothelin is present on the surface of normal mesothelial cells.1 Although the function of mesothelin is unknown, it is overexpressed in a wide variety of cancers including mesothelioma, pancreatic ductal adenocarcinoma, and ovarian carcinoma.1-6 Mesothelin has proven to be a valuable marker for pancreatic ductal adenocarcinoma due to its strong reactivity in tumor tissue and absence in normal pancreas.1, 3-4 Metastatic renal cell carcinoma can present clinical patterns that mimic primary mesothelioma, pancreatic ductal adenocarcinoma, and ovarian carcinoma.2, 4-6 Mesothelin has demonstrated utility in the differential diagnosis between these primary tumors and corresponding metastatic renal cell carcinoma within the context of an antibody panel.4-6